Isaiah 56:6-7

And foreigners who join themselves to the LORD, to minister to him, To love the name of the LORD, to become his servants— All who keep the sabbath without profaning it and hold fast to my covenant, Them I will bring to my holy mountain and make them joyful in my house of prayer; Their burnt offerings and their sacrifices will be acceptable on my altar, For my house shall be called a house of prayer for all peoples.